The present invention relates to a walk behind self-propelled crawler snowplow having driving wheels mounted on a vehicle body for driving the snowplow, an auger for removing snow, and left and right handlebars extending from a rear end of the vehicle body in a rearward direction of the snowplow.
Walk behind self-propelled crawler snowplows are known from Japanese Patent Laid-open Publications Nos. (SHO) 63-223207, (HEI) 02-38606 and (HEI) 03-107009. The known snowplows have left and right operation handlebars extending from a rear end of a vehicle body, and a snow-removing mechanism including an auger and a blower that are mounted on a front portion of the vehicle body. During snow-removing operation, the auger and the blower are driven while the handlebars are properly manipulated to keeping a desired traveling posture of the snowplow. In general, the snowplows have various operation control levers that are manipulated to control travel conditions of the vehicle body and drive conditions of the auger and blower. A typical example of the conventional operation control levers will be described in greater detail with reference to FIGS. 20A and 20B.
As shown in FIGS. 20A and 20B, left and right operation handlebars 100L and 100R extending from a rear portion of the vehicle body (not shown) each have a grip 101L, 101R. A travel control lever 102 is pivotally mounted via a bracket 102a to the left handlebar 100L in the proximity of the grip 101L. An auger control lever 103 is pivotally mounted via a bracket 103a to the right handlebar 101R in the proximity of the grip 101R.
In operation of the snowplow, the travel control lever 102 is manually operated to swing in a direction indicated by the arrow shown in FIG. 20A. By thus swinging the travel control lever 102, a power transmission belt associated with a travel clutch (neither shown) for actuating the same is stretched or tensioned to thereby place the travel clutch in the engaged condition or state. The travel clutch enables power to be transmitted to driving wheels (not shown).
The auger control lever 103 is manually operated to swing in a direction indicated by the arrow shown in FIG. 20B. With this angular movement of the auger control lever 103, a power transmission belt associated with an auger clutch (neither shown) for actuating the same is stretched or tensioned to thereby place the auger clutch in the engaged state. The auger clutch enables power to be transmitted to an auger (not shown).
To keep the travel control lever 102 in its operating position, it is necessary for the human operator to continue gripping of the travel control lever 102 using its left hand. However, due to a great force required to tension the power transmission belt to actuate the travel clutch, continued gripping of the travel control lever 102 means that a great force F (FIG. 20B) must be continuously applied to the travel control lever 102 so as to keep the lever in its operating position. With this requirement, the left hand of the human operator is subjected to undue load when the snow-removing operation continues for a long time. A similar problem occurs when the auger control lever is operated with the right hand of the operator so as to keep the engaged state of the auger clutch.
FIG. 21 shows another example of the conventional operation control levers, which is disclosed in Japanese Patent Laid-open Publication No. (HEI) 02-38606. As shown in this figure, a travel control lever 102 mounted to the left handlebar 100L and an auger control lever 103 mounted to the right handlebar 100R are connected together by a connecting mechanism 105. The connecting mechanism 105 is arranged such that when the auger control lever 103 is operated to swing toward an operating position while the travel control lever 102 is held in its operating position, a locking cam (not shown) of the connecting mechanism 105 engages the auger control lever 103 to thereby lock the lever 103 in the operating position.
So long as the operator continues gripping of the travel control lever 102 to maintain a force F exerted on the lever 102, the auger control lever 103 is held in its operating position even when the operator releases the lever 103. The right hand of the operator is thus freed from the auger lever handling work and is able to undertake manipulation of other levers and switches. This may increase the working efficiency of the snowplow.
The connecting mechanism 105, which is provided to lock the auger control lever 103 in its operating position while allowing the operator to release the same lever, gives rise to a problem that the snowplow is rendered complicated in construction and costly to manufacture. Additionally, due to the structural complexity, the snowplow requires much labor for maintenance.
It is accordingly an object of the present invention to provide a walk behind self-propelled crawler snowplow, which can be maneuvered with reduced labor, is relatively simple in construction and can be manufactured less costly.
According to the present invention, there is provided a walk behind self-propelled snowplow comprising: a vehicle body; at least one driving wheel mounted on the vehicle body for propelling the snowplow; a first power transmitting mechanism; an electric motor that drives the driving wheel via the first power transmission mechanism; a snow-removing auger mounted on the vehicle body; a second power transmission mechanism; a power source that drives the auger via the second power transmission mechanism; an electromagnetic clutch incorporated in the second power transmission mechanism for the connection and disconnection of the power source and the auger; left and right handlebars extending from a rear end of the vehicle body in a rearward direction of the snowplow; a control board disposed between the left and right handlebars; a travel ready lever mounted to one of the left and right handlebars and adapted to be gripped by a human operator to place the electric motor in an operative condition; and a clutch control pushbutton switch disposed on the control board at a position close to the other handlebar, the clutch control pushbutton switch being adapted to be manually operated to actuate the electromagnetic clutch.
Use of the travel ready lever and the clutch control pushbutton switch in combination enables the operator to maneuver the snowplow with reduced labor, makes the snowplow relatively simple in construction.
In one preferred form of the invention, the first power transmission mechanism includes an electromagnetic brake, and the travel ready lever comprises a brake control lever operatively connected to the electromagnetic brake in such a manner that when the brake control lever and the one handlebar are gripped together by the human operator, the electromagnetic brake is released to thereby allow power from the electric motor to be transmitted to the driving wheel.
The snowplow may further include a brake control switch operatively connected to the electromagnetic brake. The brake control switch is adapted to be actuated by the brake control lever to disengage the electromagnetic brake when the brake control lever and the one handlebar are gripped together by the human operator. Preferably, the clutch control pushbutton switch is connected to a power supply via the brake control switch.
It is preferable that the clutch control pushbutton switch and the travel ready lever are operationally linked with each other. The snowplow may further include a travel ready switch adapted to be actuated by the travel ready lever to place the electric motor in the operative condition, the clutch control pushbutton switch being electrically connected with the ravel ready switch. In another preferred form of the invention, the electromagnetic clutch and the travel ready lever are operatively connected together via the travel ready switch and the clutch control pushbutton switch in such a manner that the electromagnetic clutch is engaged and disengaged when the clutch control pushbutton switch is actuated while the travel ready lever is being gripped together with the one handlebar, the electromagnetic clutch is forcibly disengaged when griping of the travel ready lever is released after the clutch control pushbutton switch is actuated to engage the electromagnetic clutch, and the electromagnetic clutch is engaged and disengaged when clutch control pushbutton switch is actuated while the travel ready lever is released.
In a further preferred form of the invention, the snowplow further include a travel ready switch adapted to be actuated by the travel ready lever to place the electric motor in the operative condition, and a U-shaped bracket attached to the one handlebar so as to define therebetween a hollow space. The travel ready switch has a switch body received in the hollow space of the U-shaped bracket and attached to the bracket, an actuator retractably mounted on the switch body and projecting outward from an open end of the U-shaped bracket. The travel ready lever has a pusher part normally held in abutment with the open end of the bracket and closing the open end of the bracket while forcing the actuator of the travel ready switch in a retracted position. The pusher part is displaced away from the open end of the bracket to thereby allow the actuator of the travel ready switch to project outward from the open end of the bracket when the travel ready lever is gripped. The pusher part of the travel ready lever may be integral with a body of the travel ready lever. Alternatively, the travel ready lever may be composed of a lever body and a pusher member pivotally connected with the lever body, the pusher member forming the pusher part. The lever body has an engagement portion normally spaced from the pusher member, the engagement member being engaged with the pusher member to pivot relative to the lever body in a direction away from the open end of the bracket as the lever body approaches the one lever. The open end of the bracket forms a stopper engageable with a part of the travel ready lever to limit a range of pivotal movement of the travel ready lever.